/*
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.jasper.compiler;

import java.util.Stack;
import java.util.Hashtable;

import javax.servlet.jsp.tagext.VariableInfo;

/**
 * Common stuff for use with TagBegin and TagEndGenerators.
 *
 * @author Anil K. Vijendran
 * @author Hans Bergsten [hans@gefionsoftware.com] (changed all statics to
 *         regular instance vars and methods to avoid corrupt state and
 *         multi-threading issues)
 */
abstract class TagGeneratorBase extends GeneratorBase {
    private Stack tagHandlerStack;
    private Hashtable tagVarNumbers;

    class TagVariableData {
        String tagHandlerInstanceName;
        String tagEvalVarName;
        String tagExceptionCheckName;
        TagVariableData(String tagHandlerInstanceName, String tagEvalVarName) {
            this.tagHandlerInstanceName = tagHandlerInstanceName;
            this.tagEvalVarName = tagEvalVarName;
            this.tagExceptionCheckName = tagHandlerInstanceName + "_exceptionCheck";
        }
    }

    /**
     * Sets the tag handler nesting stack for the current page.
     * Called when an instance is created.
     */
    protected void setTagHandlerStack(Stack tagHandlerStack) {
        this.tagHandlerStack = tagHandlerStack;
    }

    /**
     * Sets the tag variable number repository for the current page.
     * Called when an instance is created.
     */
    protected void setTagVarNumbers(Hashtable tagVarNumbers) {
        this.tagVarNumbers = tagVarNumbers;
    }

    protected void tagBegin(TagVariableData tvd) {
	tagHandlerStack.push(tvd);
    }

    protected TagVariableData tagEnd() {
	return (TagVariableData) tagHandlerStack.pop();
    }

    protected TagVariableData topTag() {
	if (tagHandlerStack.empty())
	    return null;
	return (TagVariableData) tagHandlerStack.peek();
    }

    protected String getTagVarName(String prefix, String shortTagName) {
	// Fix: Can probably remove the synchronization now when no vars or method is static
	synchronized (tagVarNumbers) {
	    String tag = prefix+":"+shortTagName;
	    String varName = prefix+"_"+shortTagName+"_";
	    if (tagVarNumbers.get(tag) != null) {
		Integer i = (Integer) tagVarNumbers.get(tag);
		varName = varName + i.intValue();
		tagVarNumbers.put(tag, new Integer(i.intValue()+1));
		return varName;
	    } else {
		tagVarNumbers.put(tag, new Integer(1));
		return varName+"0";
	    }
	}
    }

    protected void declareVariables(ServletWriter writer, VariableInfo[] vi,
                                           boolean declare, boolean update, int scope)
    {
        if (vi != null)
            for(int i = 0; i < vi.length; i++)
                if (vi[i].getScope() == scope) {
                    if (vi[i].getDeclare() == true && declare == true)
                        writer.println(vi[i].getClassName()+" "+vi[i].getVarName()+" = null;");
                    if (update == true)
                        writer.println(vi[i].getVarName()+" = ("+
                                       vi[i].getClassName()+") pageContext.findAttribute("
                                       +writer.quoteString(vi[i].getVarName())+");");
                }
    }
}
